7mm ultra mag reloading issue

[R700ultra]

My factory barrel ultra mag was replaced with a criterion remage barrel. The chamber tolerances are closer on the new barrel and my resized fired brass will not fit in the new barrel's chamber. I have some new brass the work just fine. The new brass is 0.545 inches near the rear of the case. The resized brass from my rcbs full lenth die is 0.549 inches. Can i buy a die that will put the brass back under that 0.545 inch size again or is the brass junk for this barrel?

 

[FearNoWind]

You might want to try a small body die but, IMO, unless you've got an awful lot of brass that you want to match up with this new barrel I'd recommend dumping the old stuff and starting with all new.

 

[R700ultra]

I have over 100 rounds of brass to get working. With it being at almost $2.00 a round. I really dont want to move on to new brass.

 

[Rich Coyle]

Small body die.

 

[R700ultra]

I am only seeing listings for a "body die" not a small body die for a 7mm ultra mag. Am I to assume they are that same thing?

 

[AZShooter]

I have made two "small base" dies by cutting off both ends of a FL die. The end result reduces the diameter of the area near the web. I did this for the 300 RUM and the 338 RCM.

My experiences with those two cases, custom chamber reamers combined with the thicker brass of these cases, caused hard extraction to after two firings. I could see a rubbed zone just in front of the web. The "web" sizer die solved the issue.

I used a carbide tool bit in my lathe to cut through the case hardened RCBS die. The carbide tool bit ends up useless afterwards but we have a surplus store that sells them for a buck so no big deal. The orange sparks are pretty crazy till you get to the softer metal underneath. Some fine machining and sanding yields a personalized small base die. Perhaps you can convince your gunsmith to make you one.

 

[ultraedge]

If you want to use the brass that you have now, the best solution is to have the chamber polished until your brass fits.

 

[Rich Coyle]

If you want to use the brass that you have now, the best solution is to have the chamber polished until your brass fits.

The best? That's some strong language.

 

[philipbrousseau]

google larry willis reloading and look at his magnum collet die and see if you think it will do what you want. 97$ but brass supply being what it is you may want it if it works.

 

[bigedp51]

Try pausing at the top of the ram stroke for 4 to 5 seconds when full length resizing. This reduces brass spring back and makes the case stay closer to the dies diameter.

Also dies vary in size, I have a Lee full length .223 die that reduces the case diameter more than my small base dies will do.